Microporous adsorbent from winemaking waste for the recovery of Mn( VII ) in liquid solutions

Abstract

Microporous activated carbon (MAC) was synthesized from winemaking waste and was used to adsorb Mn(VII) from aqueous solutions under various experimental conditions. Moreover, Mn(VII) adsorption on MAC was compared to other adsorbents and an ion-exchange resin, as well as those of other anionic complexes. Langmuir type-1 isotherm best fitted the adsorption process, whereas for all the studied temperatures (30 (cid:1) C-60 (cid:1) C), the experimental data fitted well with the pseudo-second-order kinetic model. The calculated activation energy was 8.1 kJ (cid:3) mol − 1 , suggesting that Mn(VII) adsorption onto the MAC was a physical adsorption driven process. A reduction of Mn(VII) to Mn(II) occurs at a pH of 1 with the precipitation of MnO 2 . Mn(VII) recovery from loaded-activated carbon using acidic conditions and different variables was investigated.